TLS_KRB5_WITH_DES_CBC_SHA

Cryptographic algorithms with low adoption should be avoided due to several critical reasons. They often lack rigorous scrutiny and testing by the broader cryptographic community, which increases the risk of undetected vulnerabilities. Moreover, their limited deployment means fewer opportunities for real-world validation and feedback, hindering confidence in their security and interoperability with existing systems. High adoption indicates robustness from extensive scrutiny and successful implementation in diverse environments.

DES should not be used in cipher suites due to its weak 56-bit key size, making it highly vulnerable to brute-force attacks. Modern standards require stronger encryption, and DES's vulnerabilities compromise security, making it unsuitable for protecting sensitive data in contemporary applications.

Chosen prefix attacks for SHA1 are feasible at an accessible cost to a well-funded adversary. This level of expense, while significant, does not pose a substantial barrier to attackers with sufficient resources, making such attacks a credible threat.

Cipher Block Chaining (CBC) mode is vulnerable to the Lucky13 and POODLE (in TLS v1.2 and below) attacks. The Lucky13 attack exploits timing discrepancies in padding validation, allowing attackers to gradually reveal plaintext. The POODLE attack leverages padding errors to decrypt ciphertext by repeatedly modifying and sending it to the server, observing the error responses. These vulnerabilities arise from CBC's handling of padding and error messages, making it less secure than modern encryption modes like Galois/Counter Mode (GCM), which offer stronger integrity and confidentiality guarantees.